[erict]

Originally Posted by dougmcp

Your golden rule is correct when working with automobiles so the wrench doesn't short anything out, in a golf cart with multiple batteries it makes no difference once you flip the tow switch.
Personally, I disconnect one of the middle connections first because it's short so that when you work on all the rest there is no connection to complete the circuit.
Unless you are having a problem with cable connections coming loose I would advise against lock washers.